The Trump administration is planning to instate a rule that will bar recipients of federal family planning funding from educating women about abortion options, making referrals to doctors that provide abortions, or providing abortion care. Conservatives have cheered the move as a way for the federal government to partially “defund” Planned Parenthood without requiring an act of Congress.

Reproductive-rights advocates are calling the policy a “domestic gag rule”—a U.S.-based version of the global gag rule that prevents U.S. aid dollars from going to any international organization that so much as acknowledges the existence of abortion. Every Republican president has instated the global gag rule since Ronald Reagan first implemented it; every Democratic president has rolled it back.

The domestic gag rule started with Reagan, too, in 1988. It affects money affiliated with Title X, the federal family planning grant program launched under Richard Nixon that provides subsidized contraception, gynecological care, and screenings for cancer and sexually transmitted infections. In 2016, the program served more than 4 million patients, about two-thirds of whom were living at or below the poverty line. Planned Parenthood is a disproportionately important player in the Title X ecosystem: Its health centers make up just 13 percent of Title X family planning providers in the U.S., but they serve 41 percent of all Title X patients.

Title X money is already barred from funding abortion care; grant recipients that provide abortions keep the money separate in their accounting. But the domestic gag rule would additionally require Planned Parenthood clinics and other abortion providers to enforce a physical separation between its Title X–funded services and its abortion work, with separate staff dedicated to each. Doctors providing family planning care to Title X patients would not be able to discuss abortion at all.

When Reagan first instituted the rule, Planned Parenthood and other reproductive-rights organizations immediately sued the federal government, claiming the rule violated caregivers’ rights to free speech and women’s rights to a constitutionally protected medical procedure. “The regulations will…censor communications between doctors and other health professionals and their patients on matters of vital medical significance,” read a complaint Planned Parenthood filed against then–Health and Human Services Secretary Otis Bowen. “The failure to provide complete information about pregnancy management at the earliest possible point in the pregnancy, and the failure to make necessary or appropriate referrals as early as possible, will often result in delays in, or failure of, a patient to obtain proper care.”

A federal court granted a preliminary injunction, but the Supreme Court allowed the rule to go into effect in 1991. In a 5–4 vote in Rust v. Sullivan, the court held that the rule did not constitute censorship. “This is not a case of the government ‘suppressing a dangerous idea,’ but of a prohibition on a project grantee or its employees from engaging in activities outside of its scope,” the opinion read. “The regulations do not violate the First Amendment free speech rights…since the government may make a value judgment favoring childbirth over abortion, and implement that judgment by the allocation of public funds. In so doing, the government has not discriminated on the basis of viewpoint; it has merely chosen to fund one activity to the exclusion of another.” The opinion also noted that “the government has no constitutional duty to subsidize an activity merely because it is constitutionally protected.”